Automatic weighing machine



June 8, 1948. A. OQSILER AUTOMATIC WEIGHING MACHINE 6 Sheets-Sheet 1 Filed May 11, 1944 June 8, 1948. A. o. SILER AUTOMATIC WEIGHING MACHINE 6 Sheets-Sheet 2 Filed May 11, 1944 June 8, 1948.

Filed May 11, 1944 A. o. SILER 2,442,907

AUTOMATIC WEIGHING MACHINE 6 Sheets-Sheet 5 June 8, 1948. A. o. SlLER AUTOMATIC WEIGHING MACHINE 6 Sheets-Sheet 5 Filed May 11, 1944 June 8, 1948. A. o, SILER 2,442,907

AUTOMATIC WEIGHING MACHINE Filed May 11, 1944 6 Sheets-Sheet 6 ma; mymm Patented June 8, 1948 UNITED STATES PATENT OFFICE AUTOMATIC WEIGHING MACHINE Arvid Ouchterlony Siler, Richmond, Va.

Application May 11, 1944, Serial No. 535,085

3 Claims. 1

This invention relates to a machine for automatically weighing and dispensing or vending bulk material. While it is adapted for the handling of any quantity of any type of solid bulk material, and with certain modifications for the handling of liquid material, it is particularly adapted for weighing and dispensing small quantitles of material such as coal.

A large amount of coal is sold by retail dealers in very small amounts to persons who do not have sufiicient means at any one time to purchase even as much as a quarter of a ton of coal. Much of this coal is sold in bags containing as little as ten or twenty pounds. The overhead in handling coal in small quantities is tremendous as the retailer not only has to take the necessary time to weigh out the coal but he is also frequently called upon to furnish strong bags in which the purchaser may carry the coal away. As in the end the overhead has to be borne by the purchaser, he pays a very high price, figured on a ton basis, for the coal. The interruptions caused the dealer by purchasers seeking such small amounts of coal is very bothersome. However, they have to be endured. The net result is that sales of coal in such quantities is satisfactory to none of the parties concerned.

The object of the present invention is to provide a practical machine which will automatically weigh out a predetermined amount of material such as coal and deliver it to the purchaser. In order that the machine shall not require the attention of an attendant it is coin or check controlled, and, after insertion of the proper coin or check is operable by the purchaser. With such a machine it is only necessary that the dealer maintain a supply of coal in the hopper which supplies the machine. The overhead heretofore attendant upon the sale of small quantities of coal is eliminated and the dealer can afiord to give the purchaser as much as 33 more coal for the same amount of money and still make a reasonable profit on the sale.

Such a machine, to be commercially practical, must be simple so that it can be sold to the retailer at a relatively low price, accurate so that the purchaser will get full weight, but no more, simple to operate, and so constructed that unscrupulous persons cannot interfere with its normal operation.

In order that the machine of the present invention shall have embodied therein the above features, it is so arranged that when a proper coin has been inserted a power shaft may be operated to cause coal to be gradually fed into a weighing hopper. When the predetermined amount of coal has been fed into the weighing hopper it overcomes the weight of a counterpoise and causes the operation of mechanism which looks the power shaft against further rotation to prevent an overweight of coal being furnished. After the power shaft has been locked against further rotation, but not before, the purchaser may cause the opening of a door in the lower side of the weighing hopper and permit the coal to flow therefrom into a discharge chute from which it may run into a bucket or bag furnished by the purchaser. If desired there may be associated with the automatic weighing and dispensing machine a bag vending machine adapted to furnish the purchaser, either gratis, or for a nominal amount, a bag into which he may cause the coal to be dumped.

After the coal has flowed from the weighing hopper the weight of the counterpoise causes the hopper to be lifted again to its original, coalreceiving position, but the power shaft remains locked against rotation until the insertion of another coin, when the machine may again be operated as before.

The invention also includes means whereby a machine as above described may be associated with a silo or other large coal storage place and equipped with means remotely controlled, as from the oflice of the coal dealer, whereby coal in large amounts may be dispensed to trucks or the like.

Heretofore, the practice generally followed in connection with the delivery of coal has been for the driver to get his order at the ofiice of the coal dealer, proceed to the silo or other place of storage where an amount of coal approximating the desired weight is loaded into the truck and return to the yard of the dealer where the load is weighed. If the load contains more than the amount desired the excess is shoveled off into bins adjacent the scales. If the load is underweight the deficiency is supplied from coal in the bins. With the present invention this primitive method is abolished.

The invention will be described in connection with the accompanying drawing, but it is to be understood that thisfurther illustration and description is by way of exemplification and that the invention is not limited thereto, except as is specifically set forth in the subioined claims.

In the drawings:

Fig. 1 is a side elevation of the operating mechanism of a machine embodying the invention, the

outer casing of the machine being shown in section;

Fig. 2 is a vertical sectional view taken on line 22 of Fig. 1;

Fig. 3 is a horizontal sectional View taken on line 33 of Fig. 1;

Fig. 4 is an enlarged view of the locking mechanism, the same being viewed from the side opposite that shown in Fig. 1, and the parts being shown in locked position;

Fig. 5 is a sectional view taken substantially on line 5-5 of Fig. 4 with the locking ratchet and pawl being broken away;

Figs. 6 and 7 are perspective views respectively of the locking pawl and the mounting means therefor;

Fig. 8 is a vertical sectional View through the weighing hopper and associated mechanism, the same being taken on line 8-8 of Fig. 3;

Fig. 9 is a perspective View of the means for effecting the release of the discharge door of the weighing hopper;

Fig, 10 is a horizontal sectional .view taken on line ifi-lil ofFig. 1;

Fig. 11 is a detail sectional view of the mounting for the weighing hopper;

Fig. 12 is a detail view showing an over-running clutch for the power'shaft operating-mechanism; and

Fig. 13 is a diagrammatic view of a modified arrangement wherein electrical means are employed for locking the power shaft against rotation when a predetermined amount of coal has been supplied to the weighing'hopper.

In the drawings, the numeral I designates a casing enclosing the operating mechanism of an automatic weighing and Vending machine whereby the same may not be tampered with, or operated, except in the manner contemplated. In use the machine will be located adjacent a discharge opening of a silo or other bin 2, which will hold a relatively large amount of the coal or other material to be dispensed.

Coal flows from the bin 2 into a receiving hopper 3 located at the upper portion of the ma-' chine. The bottom of the hopper 3 is formed by theupper flight of an endless conveyor 4, which passes around pulleys 5 and B secured to shafts l and 8 respectively. The shaft Tis fixed to the frame of the machine, but the shaft 8 is movable longitudinally of the conveyor under the influence of a tightening spring 9, whereby the conveyor is at all times maintained under the desired tension. The conveyor 4 inclines upwardly toward the discharge end to prevent flow of the coal from the receiving'hop'per 3 to the weighing hopper H, except when the conveyor is being operated to pull the coal along to the discharge end thereof.

As shown in Figs. 1 and 2, a sprocket I2 is secured to one end of the shaft 7 and turns therewith. A chain 13 passes around the sprocket [2 and around a similar sprocket l4 secured to a shaft l5 mounted in the frame of the machine. The shaft |5 also carries a second sprocket is, around which the upper portion of an endless chain l1 passes. The lower end of the chain ll passes around sprocket 18 secured on a shaft l9 mounted in bearing 19'. The shaft l9 carries a gear 2i which meshes with a gear 22 on a main powershaft 23. As the power shaft 23 is located at the rear of the machine and as it is desired to have it operable from the front of the machine it carries a sprocket 24 around which one end of an endless chain 25 passes. Theother the conveyor 4.

end of the chain 25 passes around a sprocket 26 on a shaft 27 located at the front of the machine. The shaft 2'! protrudes through one side of the casing I and has an operating handle 28 secured thereto. The shaft 21 is preferably provided with an over-running clutch 27' of any desired form, whereby any undue strain placed upon the handle 28 will not affect the operating mechanism.

' 'By turning the handle 2i? movement may be imparted to the power shaft 23 and through the several sprockets and chains just described to However, such movement is normally prevented by a locking pawl 29 having teeth 36 engaging the teeth of a ratchet wheel 3'! rigidly secured to and rotatable with shaft 23, as will more fully appear from the following description. Movement of shaft 23 in the reverse direction is prevented by a ratchet wheel 32 and a spring-pressed pawl 32'.

As has just :been stated, the pawl 29 normally locks the shaft 23 against rotation to prevent 'movement being imparted to the conveyor 4 .to

discharge coal into hopper H. The unlocking of the pawl is controlled by a coin or check-controlled mechanism 33 :of standard construction. The coin-control mechanism per se forms nc part of the present invention and Will'not be described in detail. It is sufficient to point out that "when a proper coin is inserted in an opening 34 .(Fig. 3), a bar 35 may be pushed inwardly a distance sufficient to cause its inner end to engage the end 35 of a rod 37 slidabl'e in a guide 3'! and move it to the right in Fig. l (to the left in Fig. 4). When the ro'd'3'! is thus moved its other bent end portion 38 engages a lateral extension .39 of the locking pawl 29 and moves it longitudinally a distance suliicient to cause the teeth 30 to become disengaged from the teeth of the ratchet wheel 3|. Such longitudinal movement of the pawl 29 is made possible by pin-and-slot connections 4| and 42 which the pawl has with a casting 43 on which it is mounted. a

To assist in maintaining the pawl 29 in locked position except when coal is actually being. discharged and to impart a quick and positive movement thereto, the pawl carries at the end remote from the teeth 30, an extension '44 which has notches 45 on each side near its outer end. Flat leaf springs 66 are sprung into the notches and corresponding notches 41 in extensions 58 on the upper side of the casting 43 (Fig. 7). The springs 45 hold the pawl in either locked or unlocked position until the proper mechanism is operated to shift it from its position, and provide means for imparting a snap action to the pawl the instant-the notches 45 pass in either direction beyond a line drawn through the notches 41.

The weighing hopper H has knife-edged trunnions 5| extending from each side which are received in bearings 52 depending froma rectangular frame 53. The frame 53 is supported by hangers '54 which have angular knife-edged extensions 55 received in bearings 55 depending from the stationary member 57' forming a 'part of the framework of the machine. The lowerends of the hangers are threaded to receive thewing nuts 54, whereby the position of the frame may be accurately adjusted to cause operation of the parts at exactly the proper instant. The frame 53 carries a pair of bars 58 along which counterpoises 59'may be adjusted to predetermine the amountof coal which will be dispensed by the machine at each operation.

' The bearings 52, frame 53, and bearings 56 form amounting for the weighing hopper which permits it to move downwardly when the weight of the coal therein overcomes the weight of the counterpoises 59. A link 60 pivoted at one end to the framework and at its other end to a projection 60 extending from the hopper, acts as a guide for the hopper during its downward movement and prevents free swinging of the hopper in the bearings 56. The extent of the downward movement of the hopper is limited by a strap 60 which the front end of the frame engages when the hopper has moved downwardly a sufficient distance.

As the bearings 56 are immovable, a downward movement of the hopper H will cause the frame 53 to swing slightly to the right in Fig. 1 (to the left in Fig. 4) about the trunnions 55 as a center with the result that the end of the frame remote from the hopper will be raised slightly. That end of the frame carries an upstanding lug 6i to which one end of a link 52 is pivotally mounted at 63. The other end of the link 62 is pivotally connected at 36. to a lever 65, which, in turn, is pivoted at 66 to a ing 6! extending upwardly from a rigid frame member 68. Link 69 has a pivotal connection 10 at one end with the lever 65, and a pivotal connection H at its other end with one end of a lever 12. The lever 12 is pivotally connected at an intermediate point 13 to a stationary lug M forming a part of the rigid frame member 68. The other end of the lever 12 is pivotally connected at 75 to one end of a link 16. The other end of the link 76 is connected to the pawl 29 by a screw 11 passing through a slot T1 in the end thereof. The slot ll permits the link 16 to move in the reverse direction when the hopper rises without disengaging the pawl 29 from the teeth of the ratchet 3|, and provides for a certain delay in moving the pawl into locking engagement with the ratchet during the descent of the weighing hopper.

With the arrangement of links and levers just described, it will be noted that as the hopper descends under the weight of the coal therein, the frame 53 will swing counterclockwise in Fig. 1 about the trunnions 55 as a center, thereby causing the end to which the link 62 is pivoted to be-raised. Upward movement of that end of the frame 53 causes link 62 and lever 65 to assume a position more in alignment, with the result that the lever 65 and'link 69 are moved to the right in Fig. 1 (to the left in Fig. 4) Such movement of link 69 will swing lever 12 about its pivot 13 in a counterclockwise direction in Fig. 1 or clockwise in Fig. 4, and move link 76 so that it will slide the pawl 28 to a position in which the teeth 30 thereof engage the teeth of the ratchet 3| and lock the shaft 23 against further rotation. The parts are shown in that position in Fig. 4. However, as the pin 11 lies in the end of the slot remote from the end of the link 16 when the pawl is disengaged from the ratchet 3!, the movement of the pawl into engagement with the ratchet does not take place immediately upon the hopper beginning its downward movement. But when the lost motion provided by the slot I1 is taken up and the pawl begins to move to engage the ratchet that movement will be accelerated by the springs 46 as soon as they pass dead center, with the result that the pawl is given a snap action to bring it into locking engagement with the ratchet. Such delayed action prevents the pawl from looking the power shaft 23 against rotation due to any slight downward movement being imparted to the hopper, as for instance by the impact caused by the initial flow of the coal into the hopper, and insures that the shaft 23 is not locked against rotation until a sufficient amount of coal has been delivered to the weighing hopper II to cause it to overcome the weight of the counterpoises 59.

The proper amount of coal having been discharged into the weighing hopper, it having descended, and the pawl 29 having engaged the ratchet 3| to prevent further movement being imparted to the power shaft 23 and consequently the conveyor 4, the coal is now ready to be discharged into a chute C for delivery to the purchaser. The chute C has a bend therein so that it is impossible for an unscrupulous person to insert his arm or a tool up the chute to interfere with the normal operation of the machine. The lower end of the chute protrudes through the front of the casing so that the coal may flow into a sack or other container for the same.

The lower end of the weighing hopper is normally closed by a door 18 swingable about the shaft 18' as a center. The door 18 is held in closed position by a latch 19 pivoted at 89 to the side of the hopper. The latch has a curved arm 8| extending from one side against which bears a fiat leaf spring 82 having one end attached to the hopper. The spring tends to move the latch about the pivot 83 to maintain the latch in position to hold the door closed.

For discharging the coal in the weighin hopper II a series of links and levers for releasing the latch 19 are provided. These include a link 83 having one end 84 extending through the front of the casing where it is readily accessible and its other end pivotally connected at 85 to one end of a bell crank lever 86, pivoted at 81 to a member 88 formin a part of the framework of the machine. The other end 89 of the bell crank has pivotally connected to one side thereof a depending link 90 which is pivotally connected at its lower end to one end of a lever B! pivoted to a fixed part of the framework. The other end of the lever 91 carries an adjustable set screw 92 which bears against the lower side of the latch arm 8| when the hopper II has descended. Thus, when the end 84 of the link 83 is pushed inward, the bell crank 86 is rotated about the pivot 81 and causes the vertical link 90 to be depressed. Such movement of the link 90 causes lever B! to be swung about its pivot and the end carrying the set screw 92 to be raised. As the set screw 92 bears against the lower side of the latch arm 8!, that arm will also be raised, and the latch 19 swung about the pivot to release the door 18 to permit the coal to flow into the chute C. A spring having one end secured to the pivot 85 and its other end to a part of the framework tends to maintain the lever 83 in its outer position.

In order that the discharge door 18 may not be released while the hopper I I is being filled and until the full amount of coal to be dispensed has been supplied to the hopper and the hopper has descended to its lowermost position under the weight of the coal, and the pawl 29 has been moved into position to lock the shaft 23 against rotation, the end 39 of the bell crank 35 is also connected to one end of a link 93. As best shown in Figs. 2, 5 and 9, the other end of link 93 is pivotally connected to one end of a bell crank lever 94 mounted on a part of the framework at the front of the machine. The other end of the bell crank 94 is pivotally connected to a. rearwaitdlyi'extending .linkv95. TLhe. link:.'95 ,;see1iEig. 15, .is. pivotally :connected :to ".;one fend 40f another bell crank ilever :95, "which zatritscother sendil has 1 agpin' andi slot :connection: 97 .Withxa pin :98 slidable ina bore :99fformed in 'thetcastin fidi-on .the diameter or" the bore :99. -When theweighing hopperwhas descended. and caused pawl-.29 'rto :-be

.moved into locking enga'gement with .theratchet 3i, that is, WhGII'it :is in the position shown in Figs. 4 and 5, the apertureJQTwill "register with the bore 99 so that the :pinis free .totmove into the aperture. At'all other times .theaperture. N12 is out of-alignment and the pin 98 is not: free t;s1ide in the bore 99. As the link r931=is con nected to the-end 89- of the bell cranklever fifi,

.aswinging of that lever about .itszpi-vot imparts movement tothe link 9-3 .as well:aseithe linkizeli. The movement oflink '53 rotates .bellzcrank lever -94 about itspivot andcauses flinkiflato J-turn;

bellcrank lever 'et-about its pivot in aclockwise direction. Such '1I1'10V61I18l1l7 :of-uthe 'ibell crank lever 96 :will cause the ,pin QB 'tO IXlOIl/EfilltOlthG aperture I02 of the pawl 29. However,;if the aperture W2 is not. in alignment with'theapin 98, the pin and associatedlin'ks anti 'leveraincluding the 1 discharge lever 83, .cannot move.

Therefora the ,pin !98 forms an effective -.means 'of t preventing :anydischarge of :coal from tithe weighing-hopper :until after :the hopper has-v descended.:unclerthe -weight ofthe coal :toebe delivered. If itwere-inot for-:t-hexpin-.-98,"- it;;iwou1d be possihle for the latchw'lfi which holds the .door lfipclosed to be released before-the weighing -;hopper H descends and rlccks the shaftlzazagainst further rotation.

. After thewveighing hopper has descendedcand thecoal containecitherein has been -released%:in

the .manner just; described the .counterpoises-rzfifi willscause thehopper to be raised againto'its .coa'l receiving position.

The: discharge door 78 has extensions is! 53 .car-

- ried-at-eachside thereof. The endsof these eextensions are provided-with :rollers 1M which, :as the edoor risescengage the overhanging; portion .lii iaof *brachets its securedto the member 186 constitut-inga 5138-3112 of the framework 10f the maohine.

As the hopper rises the rollers Y i 64 engage the overhanging; portions :of' the brackets i235 and-cause the door to be :brought :into closed a position; iD' NVhiCh position it is held bythewlatch 19. LA counterviveightclal zcarriemby the-:door also assists :in' rotating thexdoor about the zshaft it"v to bring the door into elosed position.

The operation of the'machine' is as follows: Assuming that theweighing hopper ;is in its normal elevated position ready to receive "coal from the receiving hopper-'3, aiproper coin will be insertedin the .slot 34 of the coin controlled mechanism 33 *and thenslide .35 thereof pushed inwardly to' 'cause :itsr-innen end .to engagethe "end seer the sliding rode3'i andzmove it"tot'he right inFigu-re 1. *Aszthe rod. 31-ismoved to the right inFigure 1 '(tothe left in Figure tithe-end thereof wi-llcngage the lateral extension :39 toslide theiockingpawlfit Jtozlthe leftin Figure 4 andrcause. the teeth: thereofito become: disen- :gagedfrom? the-. teeth :of ratchet :31 won: the power shaft 223 thereby permittingmnvement to-rbeiimparted to :said. shaft. The.:purchaser rwill .t-hen "rotate the. handle '28 =-which @willimpart .move- 1 ment to the :powershaft -23 .Whichin Lturn causes -:the-.conveyor--4 to: be operated :to-discharge-coal from the r-receiving hopper 3 into the weighing hopper H. .When thepredetermined:amounttof .coal has beentdischarged into the-weighing :hop-

-.-.per all it will :descend-understhe weight thereof ..and cause the. frame :53 to .beswung .inna .counterolockwise direction-imFigurel about. the trunnions :55. -Such movement ofuthe name 53 will cause-the end carrying thealug 3! -to be-raised. As the endof the frame :53 risesithe linkifiz and thelever tend ,to movemore into alignment with the result that the lever 65swings-ito the left :in Figure 4 (to the right infligure 1).

' Simultaneously therewith the link 69 .rotatesthe lever 1 2 in a: clockwise direction (Fig.4) .aboutzits pivot .73 with :the result-that :the 'link :lfizslides the locking pawl 29 :to :'.the right in Figure -4 .a sufiicient distance to cause the lteethi3fl thereof to engage the -teeth of the ratchet 3| ion ithe power shaftf'zfi and lock the :same against-rotation. This movement. also-brings the aperture -l 02rin the .pawl ZH -intO. alignment withtheahore 99; so that the pin 98 is free to slide 'within'isaid bore.

' "The. parts having been brought into: vthe position just describedthe-coalmay nowhe zdumped from the weighinghopper. Such dischargezof the "coal .iseffected 'by thepurchasenpushingdnwardly on the lever '83 which :causes-the vertical link' -so to'be depressed "and the end-.of'theilink iciently'to' cause the latch 1:9 holding the discharge door 18 to be released,'=where.upon the coal :fiows out of the weighing hopper Pl lz'intothe rchuteqc which delivers it tothepurchaser. il -he coal having been-discharged :the hopper rises and-"the discharge door is closed :so' that-thermachine :is: again ready for another operation.

'In Fig. .13 there is diagrammatically-shown electrical means for: locking the shaft'tz Ssa'gai-nst rotation when :the hopper wl-l "descendsisunder 'the weight of the coal :contained :therein. in :this modification the paw/1129 is constantlyurged by aspring 4H0 .intoposition-to iengage theteeth 'of-rachetx wheel: 3.! on, shaft .2-3 to lock thessame against rotation, but'xmay be moved i-ntowitscdisengaged position byit-he *insertionrof.=a properzooin andpushing introdlSI. as descr'ibedrinconnection with the: form .of :therinventiom discl'osediniicon- :nection with Figs. rltto '12. When thetpawl :is

"moved to its disengaged position, .a-;tooth l'l'lwon a :pivotedilever H2 engages' a'not'ch lil3'iin the :loWer :side of thepawl :and: holdsrit in :that position' to'permit the::s'haft=23 to :be 'rota'teditoi'impart movement to :the conveyor to :supply zcoal to the hopper "I l.

The frame .153 "on "which the :hopper 2H is mounted carriesLaJcQntact il 13 adaptedztoircoop- "erate' with a :stationary contact *1 M #to 5002111318156 an electrical circuit through "the .;solenoid r'l l'5. The solenoid is 'operatively :comiecte'd through the. link i It to "the lever M2,: soithat "when'athe hopper l I descends .and fcompletesitheielectnioal circuit through the solenoid 'H 5., :theflatter-owill Pull up onlink .1115 and cause-*the.-lever tllztto 'be swung about its'apivotsufficientlytozwithdraw the tooth Ill from theinotch"l.lf3'inthe pawl, .whereupon the spring :H-D immediately moves :the .pawl to theleft :tocanse iti'toiengagezthe teeth :of the 'ratchetrwheel :31 .zandflo'ckthei shaft '23 :against rotation :until the'rhopper iragain rises :and-anothercoin is inserted.

'While' therreceptacl'e 1H 'has zheenrreferred'tto as a weighing hopper, the word hopper is not used in a limited sense and where it is referred to in the subjoined claims it is, unless otherwise qualified, intended to include any type of receptacle.

I claim:

1. In an automatic weighing machine, a supply hopper for material to be weighed, a weighing hopper positioned to receive material from the supply hopper, said weighing hopper being so mounted as to descend when a predetermined weight of material has been delivered thereto, means for causing the delivery of material from the supply hopper to the weighing hopper, a power shaft from which said delivery means is driven, means for normally locking said power shaft against rotation, said means including a ratchet wheel carried by said power shaft and a pawl normally engaging the teeth of said ratchet wheel, check controlled means for disengaging the pawl from the teeth of the ratchet wheel to permit said power shaft to be rotated to cause delivery of material from the supply hopper to the weighing hopper, means operable upon descent of the weighing hopper to move said pawl into engagement with the ratchet teeth and thereby lock said power shaft against rotation, means to restore said weighing hopper to its upper position, and means for maintaining said pawl in engagement with the teeth of said ratchet wheel after the weighing hopper is restored to its upper position and until again released by the check controlled means.

2. In an automatic weighing machine, a supply hopper for material to be weighed, a weighing hopper positioned to receive material from the supply hopper, said weighing hopper being so mounted as to descend when a predetermined weight of material has been delivered thereto, means for causing the delivery of material from the supply hopper to the weighing hopper, a power shaft from which said delivery means is driven, means for normally locking said power shaft against rotation, said means including a ratchet wheel carried by said power shaft and a pawl normally engaging the teeth of said ratchet wheel, means for disengaging the pawl from the teeth of the ratchet wheel to permit said power shaft to be rotated to cause delivery of material from the supply hopper to the weighing hopper, means operable upon descent of the weighing hopper to move said pawl into engagement with the ratchet teeth and thereby lock said power shaft against rotation, means for causing the discharge of material from the weighing hopper, and means preventing the operation of said last mentioned means until the weighing hopper has descended 10 and the pawl has been moved into engagement with the ratchet wheel.

3. In an automatic weighing machine, a supply hopper for material to be weighed, a weighing hopper positioned to receive material from the supply hopper, said weighing hopper being so mounted as to descend when a predetermined weight of material has been delivered thereto, means for causing the delivery of material from the supply hopper to the weighing hopper, a power shaft from which said delivery means is driven, means for normally locking said power shaft against rotation, said means including a ratchet wheel carried by said power shaft and a pawl normally engaging the teeth of said ratchet wheel and having an aperture therein, means for disengaging the pawl from the teeth of the ratchet wheel to permit said power shaft to be rotated to cause delivery of material from the supply hopper to the weighing hopper, means for causing the discharge of material from the weighing hopper, a pin smaller than the aperture in the pawl normally abutting the pawl and preventing operation of the means for discharging the weighing hopper, and means operable upon descent of the weighing hopper to move the pawl into engagement with the teeth of the ratchet wheel and to bring the aperture therein into alignment with said pin whereby said pin may enter said aperture and permit operation of the weighing hopper discharge means.

ARVID OUCHTERLONY SILER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 731,845 Blaisdell June 23, 1903 1,066,656 Richardson July 8, 1913 1,126,164 Williams Jan. 26, 1915 1,859,444 Howe May 24, 1932 1,895,297 Steere Jan. 24, 1933 1,911,235 Morrow May 30, 1933 2,028,544 Howe Jan. 21, 1936 2,139,903 Mason et a1 Dec. 13, 1938 2,212,419 Harmon Aug. 20, 1940 2,232,404 Pratt Feb. 18, 1941 2,258,081 Weckerly Oct. '7, 1941 2,260,718 Merrifield Oct. 28, 1941 FOREIGN PATENTS Number Country Date 15,517 Great Britain 1890 253,029 Great Britain June 10, 1926 

